The present invention relates generally to airbag modules and more specifically to a driver airbag module, however, the invention is usable with many types of modules.
A driver or passenger airbag module typically includes a housing and a frangible cover secured to the walls of the housing. The housing is configured to receive a folded airbag, which is often referred to as a bag pack, and an inflator. The most commonly used inflator in driver airbag modules is a pyrotechnic inflator. Pyrotechnic inflators are being used more often for passenger and side airbag modules. The typical pyrotechnic inflator includes a central cylindrical member which houses the fuel and one or more igniters to ignite the fuel. Additionally, extending from the cylindrical member is a flange adapted to be connected to the lower surface of the housing. Upon ignition of the inflator a significant amount of heat is generated which by convection extends out to the housing. Early housings for driver airbag modules were fabricated from metal where the excess heat was not a problem.
The present invention comprises the addition of a heat shield situated between the inflator flange and a mating surface of a plastic housing for an airbag. A gasket interposes the mating surfaces. The purpose of this gasket is to create a pneumatic or hydraulic seal.
More specifically, the invention comprises: an airbag module 20 comprising a cover 22, a housing 40 matably configured with cover 22, a pyrotechnic inflator 60 having a flange 70, and an airbag fitted within the space between housing 40 and cover 22. The airbag is inflated with gas provided by the inflator 60. The heat shield 80 is positioned between the lower surface 42 of housing 40 and a complementary surface 71 of flange 70, the heat shield protectively shields surface 42 from the heat transfer from flange 70 to prevent surface 42 from melting.